4140 bending stress 1

[dgkhan]

4140 alloy piece is quenched in oil to hardness between 44 to 48 Rochwell.The process is: Preheat 1000 degrees F for 2 hours. Process heat 1550 degrees F one hour per inch of thickness. Draw 725 degrees F one hour per inch of thickness.
what will be bending stress, yield strength?

 

[Goahead]

The old faithful MIL-H-6875 gives a tensile strength range of 200 to 220 ksi for the given tempering temperature.
About the same can be found in many Hardness Conversion tables.
A small diagram in an old edition of the Metals Handbook
gives for yield strength respectively the values of about 175 to 190 ksi but they are statistical means that cannot be used for design purposes.

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